Fire extinguishing apparatus

ABSTRACT

A fire suppression system utilizing high expansion foam has the foam concentrate held in a rupturable container immersed within a water tank so that in response to a burst of pressure introduced into the system at the outbreak of a fire, the container ruptures to charge the water with foam concentrate and to rush the resulting solution to generating hoods from which the foam is discharged to extinguish the fire. Alternative embodiments disclose a flexible bag for the concentrate or a rigidly walled container having a breakable seal that guards the outlets for the concentrate. Special structural features of the generators, including air inlet and foam outlet relationships, the disposition of an air baffle within each generator with respect to its foam outlet, and nozzle positioning cooperate to produce a high foam expansion ratio.

[4 1 Aug. 20, 1974 FIRE EXTINGUISHING APPARATUS [75] Inventor: Charles A. Ray, Kansas City, Kans.

[73] Assignee: Foamex ProtectionCorporation,

Kansas City, Mo.

[22] Filed: Nov. 16, 1973 [21] Appl. No.: 416,622

[52] US. Cl 169/65, 169/9, 169/14,

169/70, 222/94 [51] Int. Cl. A62c 3/08 [58] Field of Search 169/2 R, 5, 9, l4, 15,

[56] References Cited UNITED STATES PATENTS 3,709,302 1/1973 Stults 169/9 3,750,754 8/1973 Stults [69/9 Primary ExaminerM. Henson Wood, Jr.

Assistant Examiner-Michael Y, Mar

Attorney, Agent, or Firm-Schmidt, Johnson, Hovey and Williams [57] ABSTRACT A fire suppression system utilizing high expansion foam has the foam concentrate held in a rupturable container immersed within a water tank so that in response to a burst of pressure introduced into the system at the outbreak of a fire, the container ruptures to charge the water with foam concentrate and to rush the resulting solution to generating hoods from which the foam is discharged to extinguish the fire. Alternative embodiments disclose a flexible bag for the concentrate or a rigidly walled container having a breakable seal that guards the outlets for the concentrate. Special structural features of the generators, including air inlet and foam outlet relationships, the disposition of an air baffle within each generator with respect to its foam outlet, and nozzle positioning cooperate to produce a high foam expansion ratio.

12 Claims, 8 Drawing Figures FIRE EXTINGUISHING APPARATUS This invention relates to the suppression of fires by high expansion foam and, more particularly, to extinguishing apparatus of the aforesaid character in which the agents for producing the foam are notpremixed, but are combined with one another only upon the detection of a fire.

One important object of the present invention is to improve the speed and thoroughness of mixing heretofore available in conventional non-premix systems by using a rupturable, pressure-responsive foam concentrate container immersed directly within the body of water in a supply tank, whereby when the concentrate is discharged into the water at the outbreak of a fire, mixing begins immediately and is carried to all parts of the tank.

Another important object of the instant invention is to provide, as one form of rupturable container, a distensible bag that holds the concentrate until ruptured by a burst of pressurized fluid introduced into the system at the outbreak of a fire.

A further important object of this invention is to provide, as a second form of rupturable container, a rigidly walled container having a concentrate outlet guarded by a seal that fractures in response to high pressure imparted thereagainst.

A still further important object is to position the outlet of the rigid container adjacent the lowermost levels of the water tank whereby gas which is used as the motive force behind the concentrate to charge the water therewith can be utilized to churn the water and thereby thoroughly mix the latter with the concentrate as the gas issues from the outlet and rises toward the top of the tank.

Yet another important object of the invention is to obtain a higher foam expansion with uniform bubble size than has heretofore been possible through the provision of a specially designed foam generator having relationships between its discharge nozzles, air inlet, foam outlet, and air baffle which cooperate to yield the improved results.

IN THE DRAWINGS FIG. 1 is a simplified view of the major components in a fire suppression system employing the principles of the present invention;

FIG. 2 is an enlarged cross-sectional view of a foam generator hood of the system taken along Line 2-2 fo FIG. 1;

FIG. 3 is a horizontal cross-sectional view through a generator hood taken along Line 33 of FIG. 2;

FIG. 4 is an enlarged, fragmentary, detail view of one form of rupturable concentrate container, in the nature of a distensible bag, parts being shown in cross section and elevation with the bag partially broken away for clarity;

FIG. 5 is a side elevational view of a generator hood enlarged from that of FIG.-1;

FIG. 6 is a largely vertical cross-sectional view of a second version of the system utilizing rigidly walled concentrate containers having breakable seals guarding the outlets thereof;

FIG. 7 is a vertical cross-sectional view thereof take along line 77 of FIG. 6; and

FIG. 8 is an enlarged, fragmentary, largely crosssectional view of the lower end of a concentrate container.

The fire suppression system of the present invention includes supply means in the nature of a tank 10 for one agent used in producing foam, such agent normally being water. The tank 10 may be provided with a heating element 12 along the bottom thereof to maintain the temperature of the water within tank 10 above the freezing point. A cylinder 14 of compressed gas (normally nitrogen) is coupled in flow communication with tank 10 by a line 16 for forcing the contents of tank 10 through the remainder of the system when the system is activated. A conventional dump valve 18 in line 16 adjacent cylinder 14 controls the flow of gas from cylinder 14 to tank 10 and normally maintainsline l6 closed. Valve 18 is, in turn, controlled by a suitable sensor (not shown) which activates valve 18 when a fire is detected to detonate mechanism within valve 18 that opens line 16 for flow of gas from cylinder 14 into tank 10. A pressure regulator 20 in line 16 downstream from valve 18 controls the pressure throughout line 16,

when gas flows therethrough.

Referring particularly to FIG. 4, one form of rupturable container, in the nature of a flexible bag 22, is suspended within tank 10 for carrying a second foam producing agent 24, such as the foam concentrate. The bag 22 has a normally open mouth 26 formed by the margins of the walls 28 of bag 22 which mouth 26 is held open across line 16 by flange fittings 30 and 32 which clamp the upper margins of walls 28 therebetween. A pair of gaskets 34 on opposite sides of the walls 28 seal the fittings 30 and 32 against gas leakage. A line of weakness 36 is provided in the walls 28 of bag 22 along the bottom of the latter to provide an area within which rupturing of bag 22 may occur in order to prevent fragmentation of bag 22.

An outflow line 38 couples the tank 10 with a plurality of foam generator hoods 40 which are normally disposed well above the floor of the building structure to be protected in order for foam issuing from the generators 40 to gravitate onto the fire and smother the same. Each generator 40 comprises a housing 42 having a closed top 44, a floor 46, an air inlet 48 extending along its back face between top 44 and floor 46, and a sloping front face defined by a foraminous foam outlet 50 in conjunction with an inclined baffle 52. The sides 54 of housing 42are closed, except for triangular, foraminous pressure relief areas 56 adjacent the tip of housing 42 and coextensive in height with the foam outlet 50.

38 for supplying the foamable solution from tank 10 toa horizontally extending manifold 62 within housing 42 and supported by a vertical strut 64. A series of discharge nozzles 66 are spaced along each manifold 62 in side-by-side relationship and are directed slightly upwardly at an angle of approximately 15 from horizontal toward the front of housing 42. As shown in FIG. 2,

the size of the spray pattern from each nozzle 66 is approximately 45 measured in a vertical plane, and the nozzles 66 are so positioned within housing 42 that the lower extremity of the spray pattern as shown in FIG. 2 substantially coincides with the junction between baffle 52 and outlet 50 for reasons which will hereinafter become apparent. As shown in FIG. 3, each of the nozzles 66 has a spray angle measured in a horizontal plane of 90, and the nozzles 66 are so spaced along manifold 62 that adjacent patterns impinge upon one another as shown in FIG. 3.

In use, the tank is filled with water 68 preferably to the level illustrated in FIG. 4, the bag 22 is inserted into tank 10 and held in position by fittings 30 and 32 and gaskets 34, and concentrate 24 is added to bag 22 to the level shown. The nitrogen from cylinder 14 is free to leave the latter and enter line 16, but is not allowed to go beyond valve 18 until the outbreak of a fire. When a fire is detected, the valve 18 is detonated to open line 16 downstream from valve 18, hence allowing th gas from cylinder 14 to enter bag 22 through mouth 26, exert pressure against concentrate 24, and rupture bag 22 along the line of weakness 36, thus releasing concentrate 24 into the water 69. The above action is, of course, virtually instantaneous inasmuch as the gas from cylinder 14 is maintained at a high pressure, and once valve 18 is opened, there is no further obstruction to impede the rush of gas into bag 22. However, even though the action is essentially instantaneous and at high pressures, bag 22 does not explode into fragments, but instead simply ruptures along weakness line 36 so that flow lines 38, 60 and nozzles 66 downstream from tank 10 are not clogged with fragments of bag 22.

In view of the fact that the concentrate 24 is denser than the water 68 within tank 10, that it is pushed by high pressure gas from cylinder 14, and that it is already disposed within tank 10 at the time rupturing of bag 22 occurs, mixing of the concentrate 24 with water 68 is very effectively and thoroughly carried out as the concentrate 24 leaves bag 22 and speeds to all sections of tank 10. The pressure of cylinder 14 then causes the solution thus formed by concentrate 24 and water 68 to flow from tank 10 and be forced to the generators 40 via lines 38 and 60.

When the solution reaches the manifold 62 of each generator 40, it is discharged from nozzles 66 in the pattern illustrated in FIGS. 2 and 3 toward and through the foam outlet 50. The jets of spray moving toward the front of each housing 42 from adjacent the rear thereof causes air to be drawn in through inlet 48 for combination with the solution carried by the discharged spray to produce the foam as the spray and air engage the outlet 50. The foam thus produced by forcing the air through the openings of outlet 50 while the spray solution clings thereon is projected outwardly into space beyond outlet 50 and gravitates to the fire therebelow to smother the same.

It has been found that the baffle 52 plays an important role in obtaining a high foam expansion ratio, on the order of 750 to 1. In this regard, it will be seen that air entering the inlet 48 at the rear of each housing 42 is drawn into the spray from nozzles 66 in an essentially horizontal line across the top half of housing 42. On the other hand, the air drawn into housing 42 below the manifold 62 and nozzles 66 travels horizontally for a distance beyond nozzles 66, and then is directed abruptly upwardly into the spray pattern and toward outlet 50 to thoroughly mix withthe spray and effect the desired foam formation. In this manner, all air entering inlet 48 is very efficiently used in the production of foam, with wastage being held to a minimum.

Furthermore, the angular relationships of the nozzles 66, outlet 50 and baffle 52 to one another are important inasmuch as the spray is directed primarily toward outlet 50, and not toward the floor 46 or baffle 52, thus assuring that the solution reaches outlet 50 without appreciable decrease in velocity and without interfering with the smooth, essentially laminar fiow of air along floor 48 and baffle 52 into the spray and out of outlet 50. By providing a steeper incline for outlet 50 than baffle 52, it will be seen that the air moving parallel to baffle 52 is guided directly toward outlet 50 through the spray, instead of away from outlet 50 as would be the case if baffle 52 were inclined more steeply than outlet 50.

It has also been determined that impingement of adjacent sprays from nozzles 66 as shown in FIG. 3 is beneficial in that more air is drawn into housing 42 through inlet 48 because of this action. Therefore, the foam expansion ratio is increased, with the result that the fire suppression capabilities of the foam issuing from generators 40 increases.

Moreover, the provision of pressure release areas 56 at the front sides of each generator 40 as well as the perforated member 48 along the rear thereof cooperate to further improve the character of foam issuing from the generators 40. The member 58 along the rear of each generator 40 is especially beneficial in that ithas been found that the amount of back spray within each generator 40 is substantially reduced when member 58 is utilized.

FIGS. 6-8 relate to a slightly modified version of the system that utilizes the same generator hoods 40 and their associated structures, but differs from the arrangement previously described at the mixing end of the system. As with the first arrangement, a tank holds a supply of water 72 that is heated by an element 74 near the bottom of tank 70 and adjacent one end thereof. A pair of nitrogen cylinders 76 are supported on opposite sides of tank 70 by supporting brackets 78, and each cylinder 76 has a flow line 80 leading therefrom into the top of a vertically disposed foam concentrate container 82. A conventional dump valve 84 in each line 80 maintains the latter normally closed until such time as the valve 84 is opened in response to signals from a fire detection mechanism (not shown).

Each container 82 comprises an elongated, hollow cylinder (preferably of polyvinyl chloride material) having its lower end closed by a wall 86 having an outlet 88 therethrough that is guarded by a pressuresensitive sealing disc 90. A diffuser 92, generally of a T-shaped configuration, has a pair of oppositely directed spouts 94 that join in a common stem 96 threaded or pressed into the outlet 88. As illustrated, the diffuser 92 of each container 82 is disposed closely adjacent the bottom 70a of tank 70, and the spouts 94 are directed generally parallel to floor 70a rather than downwardly in perpendicular relationship thereto.

As shown in FIG. 6 the opposite upper end of each container 82 is open but has a cover 98 thereon provided with an inlet 100 communicating with the proximal flow line 80 from the corresponding nitrogen cylinder 76. A split ring coupling 102 firmly clamps the cover 98 against the upper end of container 82 to thoroughly seal the latter.

The solution that is mixed within tank 70 is discharged therefrom through a siphon tube 104 having an open end 106 spaced but a short distance above bottom 70a of tank 70. The upper end of siphon tube 104 may be connected to the line 38 leading to the generator hoods 40 as illustrated in FIGS. l-5.

In use the apparatus disclosed in FIGS. 6-8 functions in a similar manner to that of FIGS. 1-5, it being understood that foam is generated by the hoods 40 in the same manner as earlier described, with the only differences in operation being centered around the containers 82. When a fire has been detected and a burst of pressurized gas is directed to the concentrate 108 within the containers 82, the concentrate 108 of each container 82 exerts pressure against its sealing disc 90 until a predetermined level is reached, whereupon the disc 90 fractures sending the concentrate 108 rushing into the water 72 through the diffuser 92.

Each diffuser 92 divides the concentrate 108 issuing from outlet 88 into a pair of streams and directs such streams in opposite directions through spouts 94 so that all areas along and adjacent to the bottom 70a of tank 70 are supplied with concentrate 108.

When the concentrate 108 has been completely discharged from each container 82, the gas from behind the concentrate 108 charges through diffusers 92 and violently churns the solution in tank 70 as the gas rises in the form of bubbles toward the top of tank 70. Thus it will be appreciated that the position of diffusers 92 closely adjacent floor 70a is an important advantage of this construction in that the escaping gas can be used to thoroughly churn and mix the contents of tank 70 in order that a properly mixed solution can be formed. This action, in combination with the directional aspects of the diffusers 92 means that the contents of tank 70 are fully mixed throughout all areas thereof in readiness for producing foam .at the generator hoods 40.

As the gas continues to escape from the diffusers 92 and fills the top of the tank 70, it exerts downward pressure against the solution formed within tank 70 so that the solution is forced into the open lower end 106 of siphon tube 104, whereupon it rushes into line 38, and thence to hoods 40.

It will be recognized that another advantage is obtained in the present system beyond that previously mentioned. Specifically, by mounting the containers 82 and the siphon tube 104 within the same tank 70 as water 72, it is but necessary to employ only a single heating element 74 where climatic conditions are such that freezing of the liquids could otherwise occur. If containers 82 were disposed outside of tank 70 and freezing temperatures were prevalent, it would be necessary to provide a heating element 74 for each of the containers 82. Moreover, by the inherent nature of siphon tube 104, no standing liquid is maintained therein above the level of the water 72 within tank 70, and thus there is no danger of freezing such standing liquid.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In fire extinguishing apparatus:

a tank containing a first agent in liquid form capable of producing a foamable solution when mixed with a second agent;

a foam generator in flow communication with said tank for receiving said solution from the tank, converting the solution to foam and discharging the foam for extinguishing a fire;

an actuatable source of pressurized fluid coupled with said tank for forcing said solution to said generator under pressure in response to the detection of a fire; and

a rupturable container within said tank holding said second agent immersed within said first agent,

said container being responsive to a predetermined burst of pressurized fluid from said source when the latter is actuated by the detection of a fire to charge and thoroughly mix said first agent with said second agent whereby to produce said solution and rush the same to said generator.

2. In fire extinguishing appartus as claimed in claim 1, said container comprising a flexible, openmouthed bag suspended within said tank in position for receiving said burst of pressurized fluid through said mouth.

' 3. In fire extinguishing apparatus as claimed in claim 2, wherein said bag is provided with a line of weakness along which the bag ruptures to release said second agent.

4. In fire extingushing apparatus as claimed in claim 1, wherein said container has an inlet at one end thereof for said pressurized fluid and an outlet at the opposite end thereof for said second agent, said outlet having a seal thereacross normally closing the outlet but being breakable in response to said predetermined pressure burst to open the outlet and release said second agent.

5. In fire extinguishing apparatus as claimed in claim 4, wherein said pressurized fluid is a gas, said outlet being located adjacent the bottom of said tank whereby said gas issuing from the outlet after discharging the second agent from the container churns through the first and second agents to rapidly and thoroughly mix the same as the gas rises toward the top of the tank.

6. In fire extinguishing apparatus as claimed in claim 5, wherein said outlet is provided with diffuser having at least a pair of dissimilarly directed spoutsfor disseminating the seond agent throughout the first agent.

7. In fire extinguishing apparatus as claimed in claim 1, wherein said generator includes a housing having an air inlet, a forarninous foam outlet spaced from said inlet, a nozzle interposed between said inlet and outlet for directing a spray of said solution against said outlet and for drawing air into said .spray from said inlet to produce foam, a floor underlying said nozzle and the outlet, and an inclined baffle leading from said floor to the outlet for directing air from said inlet to the spray and through said outlet. I

8. In fire extinguishing apparatus as claimed in claim 7, wherein said outlet is inclined upwardly away from said nozzle and at a steeper angle than said baffle.

9. In fire extinguishing apparatus as claimed in claim 8, wherein said nozzle is so positioned that one generally lateral extremity of the spray is disposed at the junction of said baffle and said outlet.

10. In fire extinguishing apparatus as claimed in claim 9, wherein the angle of inclination of said outlet is approximately forty-five degrees from horizontal, that of said baffle is approximately thirty degrees from horizontal, and that of said nozzle is approximately fifteen degrees from horizontal.

11. In fire extinguishing apparatus as claimed in claim 7, wherein is provided a series of said nozzles spaced apart in side-by-side relationship and so positioned that the sprays from adjacent nozzles impinge 12. In fire extingushing apparatus as claimed in claim 7, wherein said inlet is provided with a perforated member disposed across the same for reducing back upon one another to increase the amount of air drawn Spray in the housinginto the sprays. 

1. In fire extinguishing apparatus: a tank containing a first agent in liquid form capable of producing a foamable solution when mixed with a second agent; a foam generator in flow communication with said tank for receiving said solution from the tank, converting the solution to foam and discharging the foam for extinguishing a fire; an actuatable source of pressurized fluid coupled with said tank for forcing said solution to said generator under pressure in response to the detection of a fire; and a rupturable container within said tank holding said second agent immersed within said first agent, said container being responsive to a predetermined burst of pressurized fluid from said source when the latter is actuated by the detection of a fire to charge and thoroughly mix said first agent with said second agent whereby to produce said solution and rush the same to said generator.
 2. In fire extinguishing appartus as claimed in claim 1, said container comprising a flexible, openmouthed bag suspended within said tank in position for receiving said burst of pressurized fluid through said mouth.
 3. In fire extinguishing apparatus as claimed in claim 2, wherein said bag is provided with a line of weakness along which the bag ruptures to release said second agent.
 4. In fire extingushing apparatus as claimed in claim 1, wherein said container has an inlet at one end thereof for said pressurized fluid and an outlet at the opposite end thereof for said second agent, said outlet having a seal thereacross normally closing the outlet but being breakable in response to said predetermined pressure burst to open the outlet and release said second agent.
 5. In fire extinguishing apparatus as claimed in claim 4, wherein said pressurized fluid is a gas, said outlet being located adjacent the bottom of said tank whereby said gas issuing from the outlet after discharging the second Agent from the container churns through the first and second agents to rapidly and thoroughly mix the same as the gas rises toward the top of the tank.
 6. In fire extinguishing apparatus as claimed in claim 5, wherein said outlet is provided with diffuser having at least a pair of dissimilarly directed spouts for disseminating the seond agent throughout the first agent.
 7. In fire extinguishing apparatus as claimed in claim 1, wherein said generator includes a housing having an air inlet, a foraminous foam outlet spaced from said inlet, a nozzle interposed between said inlet and outlet for directing a spray of said solution against said outlet and for drawing air into said spray from said inlet to produce foam, a floor underlying said nozzle and the outlet, and an inclined baffle leading from said floor to the outlet for directing air from said inlet to the spray and through said outlet.
 8. In fire extinguishing apparatus as claimed in claim 7, wherein said outlet is inclined upwardly away from said nozzle and at a steeper angle than said baffle.
 9. In fire extinguishing apparatus as claimed in claim 8, wherein said nozzle is so positioned that one generally lateral extremity of the spray is disposed at the junction of said baffle and said outlet.
 10. In fire extinguishing apparatus as claimed in claim 9, wherein the angle of inclination of said outlet is approximately forty-five degrees from horizontal, that of said baffle is approximately thirty degrees from horizontal, and that of said nozzle is approximately fifteen degrees from horizontal.
 11. In fire extinguishing apparatus as claimed in claim 7, wherein is provided a series of said nozzles spaced apart in side-by-side relationship and so positioned that the sprays from adjacent nozzles impinge upon one another to increase the amount of air drawn into the sprays.
 12. In fire extingushing apparatus as claimed in claim 7, wherein said inlet is provided with a perforated member disposed across the same for reducing back spray in the housing. 